How does Blanche say she will die?

From the text:

I can smell the sea air. The rest of my time I'm going to spend on the sea. And when I die, I'm going to die on the sea. You know what I shall die of?
[She plucks a grape]
I shall die of eating an unwashed grape one day out on the ocean. I will die--with my hand in the hand of some nice-looking ship's doctor, a very young one with a small blond mustache and a big silver watch. "Poor lady," they'll say, "the quinine did her no good. That unwashed grape has transported her soul to heaven."